Centrifugal separator.



H. DE RAASLOFF & T'. E. BROWN.

CENTRIPUGAL SBPARATOR.

APPLICATION FILED MAR. 16, 1909.

1,044,570?. Patented Nov. 19,1912.

lll

-pressure or line of liquid, but are, as herein 'stood' principles of centrifugal force and vmain full of liquid; and said chambers are n sin tion from the nozzles in which extraction takes place. As the plugs are of relatively great radial length, and are removed by the conveyers at the same rate as that at which the plugs are formed, some plug remains continucusly 'in the neck of each chamber, andalways divides the liquid undergoing separation from said nozzles.

Second: The outlet orifices ofsaid separating chambers lare connected with nozzles, or chambers, wholly external to the separating chambers and extending to a point nearer the axis of rotation of the machine than the extremity of said chainber, and in fact, said nozzles extend in- Wardly at least to the line of atmospheric above stated, wholly external to the scpa rating chambers. According to well undert'rictional resistances, the plugs, were there no conveyers, would be. forced into these nozzles by the centrifugal force, until the s lopeof the surface of the plug was at the angle of friction of that particular material. and thereafter the plug would move no farther and would resist any further movement of plug from the separating chamber. That part of thev plug which .is in the said nozzle is entirely separated from and out of the way of the liquid in the separating chamber,and the vconveyer may therefore remove it Without interference with or from the liquid in the separation chamber. As the conveyer removes the out-er end of the plug, the centrifugal force moves the plug out, and the formation of the plug in the separating chamber and its removal by the conveyer go on continuously and simultane ously.

Third. The liquid outlet, or overflow, determines the line of atmospheric pressure, and the machinefis so constructed and is operated at such speed, that at this overflow the centrifugal force of the liquid just overloalances atmospheric' pressure. The machine is also so constructed, and -the flow of the materials into the separating chamber isA so controlled, that approximately zero pressure\exists at some point between the line of atmospheric pressure and the axis of rotation of the machine, and the line of zero pressure defines, by preference, the location of the inner ends of the separating chambers, said -ends being preferably located just outside the line of zero pressure. so that said separating chambers will repreferablv connected with said point of liquid discharge or overiiovv by'pipes or con- 1 duits which connect with said separating chambers just outside of said line of zero pressure. By 'the aforesaid relations of at mospherie pressure and zero pressure in the l machine. we are able to obtain, within comparatively small radial dimensions, a machine, the separating chambers of which have relatively great radial depth ofliquid in such a state of gentle flow as affords ample time for the separation and deposit of the heavy materials, and effectually obviates injurious eddies and whirls in the liquid in said separating chambers. y

Fourth. To insure removal of the plugl in the driest possible conditi on, and in a thoroughly practicable manner, the nozzles on said separating chambers have extensions, or conveyer casings, extended on a proper inclination toward-the axis of rotation, and to a point within the line of atmospheric pressure or line of liquid, so that the part of the conveyer casing Within said line of liquid constitutes adrying chamlier for the plug, centrifugal force and gravity both coopera-ting to free the plug from the liquid which may havebeen in its pores: the discharge of the plug taking place at a point well Within the said line of liquid, and it being understood that said convcyer casing, as well as said nozzles, are wholly external to said separating chambers, so that the plug, during all its movement from the point of concentration to the place of discharge, is separated from the mixture which is undergoing separation.

The principle of the machine may now be more clearly explained as follows: Suppose a vessel closed at one end and of relatively great length and relatively small cross area. and having astill more contracted neck, said neck connecting with a nozzle turned upward and backward, to be revolved around an axis perpendicular to its length: the neck being filled with a plug of finely divided heavy solid particles, and the rest of the vessel containing a liquid. Now the centrifugal force will squeeze the plug outwardly through the neck. The liquid will also move out and rise in the nozzle the inner end of the liquid forming a wall having a position and slope determined by the relation of the centrifugal force to the atmospheric pressure and gravity, and there will loe a vacuum behind the inner wall of the liquid, and the position of that wall will be the line of zero pressure, and the line of liquid in the nozzle will be at the line of atmospheric pressure. Now the neck of the vessel being connected with an external nozzle or chamber, as for example the necks of separating chambers in Figure l of the accompanying drawings are connected with the external nozzles 14, then the plug would enter the nozzle until the surface of the plug acquired the angle of friction for that plug. when the plug would advance no farther into the nozzle. Now suppose the said vessel to be provided With an escape pipe for lOl() .ll/lanifestlythe` liquid could not 'flow through colli/cycli casing, or said-nozzle, against Vthe centrifugal force andat'mospheric pres the liquid led outwardly but to a convenient vpoint preferably nearer the axis of rotation than is the point of concentration, andI at that point opened to atmosphere, but. being properly curved or trapped, and the inner end of said liquid escape pipe being connected with said vessel just outside the line of zero pressure. An illustration of a posi sible position for such pipe is given in Figs. 1 and 3 of the accompanying drawings, where the pipe is indicated by the number 28. Now suppose that the apparatus is revolved at. such velocity that the centrifugal force at the open end of said liquid discharge pipe is just equal to atmospherig: pressure. ldlainly there would be no Vdischarge of liquid by centrifugal force, the atmospheric pressure and the centrifugal force just balancing each other. Now suppose the inner end of this said vessel connected with a source of supply of the mixed liquid and solid materials, so controlled that ythe mixture can enter the vessel only at such a 'rate as will give ample time for the separation and deposit of the heavier solid particles, and without producinginjurious currents or eddies. lThe mixed materials would manifestly enter the vessel under a head equal to the hydraulic head of the mixture plus atmospheric pressure. And if the supply of the mixture to the tank or reservoir from which it flowed to the separating vessel were constant, manifestly an orifice or pipe of proper constant size connecting the reservoir with the separating vessel would be sulticient, without a controlling valve. But because of variations in the amount to -be. separated, it is desirable to use a control valve, whereby the area of the inlet orifice to the separating vessel will be varied to suit the supply admitted to the machine and thus maintain the vacuum or zero pres sure. Under the conditions assumed, it will be manifest that the discharge of the liquid from the apparatus, after separa-tion of the solid matters, will be exactly equal to the inflow, and is therefore governed by the aforesaid vhydraulic and atmospheric head,

not by the centrifugal force, and can be controlled with great nicety, and without tending to disintegrate the plug, which is formed and expelled' from the separating vessel by centrifugal force and through an outlet independent from the liquid outlet. Finally assume, that asv the plug enters the said external nozzle it is caught by a conveyer, 'which conveys it through a chamber o1' casing in sucli'a direction that the plug moves` toward the axis of rotation against the centrifugal force, and to a point nearer the axis affectation than the line `of liquid.

sure, and could never reach a point materially nearer the axis of rotation than the line of liquid; and therefore a portion of the conveyer casing would constitute a drying chamber, and the plug would be dried to the greatest possible degree by its passage through the dry part of the conveyer casing. Now as the mixture is continually flowing into the separating vessel at a uniform rate, and as the plug is'continually formingand continually being removed by the conveyer at the rate at which it is formed, the operation goes' on continuo-ns1 y, without ever clogging the separating vessel with unremoved deposits of concentration, o-r ever permitting the escape and waste of the liquid through the plug nozzles.

The apparatus illustrated in the accompanyingl drawings, and hereinafter described, illustrates two modifications of machines constructed according to the fore going principles, but it will be understood that the-invention is not restricted to suchl particular apparatus, but includes all centrifugal separators which embody/the principle of producing the separation in separating chambers provided with external nozzles for the concentrates led to a point nearer the axis oirotation than is the extremity of said chamber and also all centrifugal separators which embody the principle of the atmospheric and zero pressures' to attain the desired length and time of flow of the liquid through the machine. Y,

Referring to the drawings which accompany the specification to aid the description, Fig. 1 1s a vertical section and elevation of one form of apparatus embodying the invention. Fig. 2 is a broken plan" and horizontal section, on the line s-sof Fig. 1. Fig. 3 is a vertical section and elevation of. another.

form of apparatus embodying the invention, 1n whlch` the material 1s drawn in from below.

'Referring'to Figs. 1 and 2, .-1v is the vessel or reservoir, preferably in the form'of a pipe positioned at the axis of rot-atitn and closed atV the bottom 2, and revolved in suitable bearings 3, 4 athigh velocity by any suitable means, as gearing 8, 9. The materials to-be separated, as liquidsand solids, are

delivered into a funnel 6 fixed on the upper end of pipe l, said funnel also preferably constitutinga float chamber for cont-rolling the inletvalve, as A will be hereinafter ex-` plained. Said pipe 1 communicates near its lower end with separating chambers 10,

preferably disposed symmetrically around the axis of rotation and connected with said pipe. 1 by branch pipes 11. Each said chamber 10 is preferably relatively of greatdif mension inv a 'd1rection perpendicularfto the axis of rotation of the apparatus, vand preferably ,dividedl by a longitudinal parti as seen in F 1 and 2.

tion 15 for a portion ot its length, to prevent direct communication between the inlet and the outletV of chamber lt), and the outer end of each said chamber is also preferably contracted to form a neel; ol small cross tional area, 26 being a perforated diaphragm or partition preferably used and positioned of the heavier materials takes place in the I, outer end otl the separating chamber. Said chambers y10 are also of such length, radially vsaid chambers ll) might be without contracted necks, or might have long tubularlike necks, or might be formed of various shapes, but in all cases we consider the extremity ot said chamber to be the the chamber' or neck farthest trom the axis of rotation, and practically ivhere the connection with the nozzle or conveyer casing is made. ("oni'iected with and Iextending' upwarrflly and inwardly trom saidcasings 14 are the Worin casings 1li, which may either be connected with the ends ot' said casings llloy flange joints or in any other suitable manner, or may be integral with said casings ll, as shown in the drawings. Said worm casings 'l1/l Contain Worin conveyers lb', the shafts 1T ot which are driven al proper speed in any suitable manner, as by bevel gears lS--lS of the Worin shaft and bevel gear 1S) on a sleeve 20 turning' on pipe 1, and driven at. suitable dillerential velocity by gears 21-12 any suitable means; Q4 being brackets fixed on said pipe 1, and carrying the bearings 'tor the upper ends of the said Worm shaft 1l, and the lower ends of said sha'tts 1T being conveniently stepped ir. the lower heads ot said casings 14. We

prefer to smnewhat enlarge they upper ends j of said worm casings lll, as seen in Fig. v3,

Y to facilitate their' use as drying chambers,

and tl'e worms 1G should then preferably I he concentration part ot' specification. The inner closed ends :2T of said separating chambers 10, are located a little out-side ot the line ot zero pressure l zwzmthat is a little farther from the axis not extend to the upper ends of said casings i 143. Said casings are arranged to discharge the cencenlrates into an annular trough 25, 1

troni which they ma).Y be removed in any suitable manner. And it. is to be uncerstood that any other suitable torni otl conveyer, casing, or nozxle may be employed instead o? the worin convryer, and the conveyer, casing and nozzle shown in the ac.

compa-nying drawings and described in this the mixed liquid and heavier of rotation than is said linea-so that said chambers l0 shall remain full of liquid, when revolving at the designed velocity, and each ot' said chambers 10 will be connected with a liquid discharge pipe 2S conducted outwardly and trapped or curved at the outer end as at 29, and opened to atmosphere at the line ot' atmospheric pressure,. as indicated at 30. To lfacilitate freeing the apparatus trom air, said pipes 28 are preferably connected with the tops of said chambers l0, and are inclined upwardly toward their outlets. Said trapped ends 29 of pipes QS are preferably inclosed in trap vessels 31, having openings to atmosphere and provided nith pipes discharging into a stationary annular trough 3st, from Which the separated liquid will be drawn or discharged by any suitable means. Said trap vessels 31 may be supported by said worm casings 14-3, but have no communication withthe interior ot said casings.

To adaptthe apparatus to a. variable supply of mixture, and to a variable output controlled by supply valve 42, said pipe 1 is provided at a point above pipes 11, and preferably belonY the traps 29, with a conical valve 3S seating on a conical seat through a diaphragm S9, and said valve is suspended by a stein l0 from a lloat Ll1 operated by the rise and fall of liquid in said funnel 6, 45?

being a guide for said stern 40.

y 'lheoperation is as follows: Suppose the apparatus to be'empty and at rest; and that particles, in more or less finely divided condition, are run into said pipe 1 trom valve 42, valve 38 being closed. As the mixed materials rise in tunnel 6 they Will at 'last lift said float all, open said valve chambers 10 and connected parts with said mixed materials to such a level that thersaid materials will overtlow at the trapped end of pipe 28 and discharge aty the lower end of pipe The entry of the mixture Will also expel the air troin the machine. As soon as this discharge at pipe 33 Lis observed the machine is started revolving; if then no niore liquid is admitted .from valve 42d the overflow will continue at Q9, and the 38, and till i the,

stands at theline'` diaphragm 39 is now the height of the column of liquid in pipe 1, plus atmospheric pressure. The valve 42 is now opened and set to the desired amount, the materials flow into the funnel 6, again raise float 41, open valve 38, and thereby adjust the orifice until the inflow, due to the head and atmospheric pressure, just equals the supply from 42, and an equal overflow of liquid occurs and continues at trap Q9. The mixed solids and liquids flow gently t-hrough chambers 10, the solids separate from the liquid, collect on the sides of chambers 10, are moved outward by the centrifugal force, and concentrate in the necks 12. The materials first entering pass to nozzles 14 and are churned by the worms 16 until sutiicient plug has formed in 12 to press them to a proper consistency to resist turning. rl`he worms 16 will thereafter convey the plugs through said nozzles 14 and casings 1+ia to the upper discharge ends of said casings 14a, which, as hereinbefore stated, are nearer the axis of rotation of the machine than are the extremities of the separating chambers 1t); and from said discharge ends of said casings 1l the said concentrated materials discharge into the said troughs 25, and are con reveil away in any suitable manner.

The upper parts of the casings 1.1d constitute a drying chamber, since they extend within the liquid line, whereby the pulp is more or less dried before itis discharged from the said casings 14a; and since said worms 1.6 do not tit water tight in Asaid nozzles 14 or casings 14, or are perforatedi or arranged to permit the liquid which separates from the concentrates, as the worm raises said concentrates, to trickle through the interstices of the material under the influence of centrifugal force and gravity, and past the worm blades back to the normal "line of liquid. ln -the lase of impervious clayey plugs it will be difficult for the liquid in nozzles 1l to equalize with the liquid in chambers 10, and with such materials we prefer to ilse an equalizing pipe l5 connecting the nozzles 1-1: outside of the line of liquid with chambers 10. ln order to obtain the best results with said worms, and to obviate the revolving of the concentrates by the worms, it is preferable to ar range the wonms at about an angle of #150 with' theidireot/ion of centrifugal force, i', e. the radius, but they need not be in the plane of the axis of rotation, but may be in any convenient plane. The lighter liquid ele` ments of the mixture entering said chainbers l() flow gently baclt, without violent currents or eddies, to the connectionsl with said pipes 28, through said pipes to their trapped ends, which are just outside of and determine the. line of atmospheric pressure, out ot' said trapped ends to the trap vessels 31,and thence by the-'pipesv discharge i ratus being Ainto the trough 34. Thus the utilization of the atmospheric pressure and the zcro'pressure provides a body of liquid of such considerable radial length, as to afford proper time for the separation and concentration of the heavier materials, and avoids eddies and whirls which would injuriously affect thev separation, and this withouty unduly increasing the radial dimensions of the machine, or interfering with the proper location of` its various parts.

The machine may be started by simply setting it in rot-ation and turning on the valve 42 to the proper amount, Lbut in this case a longer time will be required to expel the air and attain theoperating conditions, hence We prefer to start in the manner described.

Referring to Fig. 3, the apparatus is shown arranged to lift the material to be separated from below by the atmospheric pressure and the vacuum induced by the centrifugal force. The separating chambers 10, nozzles 14, worm casings 14a, worms 16,

pipes Q8, traps 29, trap vessels 31, discharge` pipes 83, Vand numerous other parts are substantially the same in construction and operation with eorresponding partsof Fig. 1, and no further description of such parts is necessary. But the valve 50, which controls the orifice for the inlet of the mixed materials, is now arranged below the pipes .11., and preferal'ily to open downwardly, and in practice the said valve 50 may be arranged nearer the open lower end of pipe or vessel 1, and if desired a check valve opening upwardly may also be provided in saidA pipe l, below said valve 50, the swiveled valve stem 54 being guided by a suitable guide or` guides 57Vv Said lower open end of pipe 1 enters, the mixed materials in a vessel 53, into which vessel said materials are delivered by a pipe and controlled by a valve 5S). Said valve 50, preferably opening downwardly, is connected by the stem 54 with a lever fulcrumed at 56, and connected at its outer end to a float 58. Said pipe 1 will be closed above pipes 11. Any suitable bearing, as 63, supported on arms 64 connected in any suitable manner with the frame work of the machine, may be provided to support and aline the lower end of said pipe 1.= l

"lhe operation is as follows: The 'appa- (or both said valve and the said check valve, it' both are used) being closed, the apparatus is primed by pouring priming liquid,(which may be the same as the materials to be treated) in through trap vessels 31 "until the machine is. full. The' machine is now started up, the centrifugal force Causes the excess liquid to overflow at trap .29 and a vacuum' is formed in pipes 1 and 11 as before. rl`hesupply valve 59 is opened the' proper aniount, the materials rise in vessel preferably at rest, and valve 50, f

' means. ln Fig. 3 we also show a scraper 8O ing screens in the troughs (38, said screens 523, the float 58 opens the valve 50 and adjusts the area of the orifice to suit the supply admitted by valve 5t); the atmosphere presses on the surface of the materials 'in vessel 53, 'auscs them to rise in pipe l, and the centrifugal force projects the mixed materials outwardly from pipe l into chambers 10, where the separation takes place, and the plugsl form and are removed by the worms lo as before, while the lighter liquid tlou's by pipes 28-to trap vessels 3l, and thence by pipes 33 to the troughs 68, which may be -provided- \vith filtering` screens as .vill be hereinafter described.

.i priming pipe and valve may he attached to the apparatus, but we prefer to prime as above described, and avoid pussibie leakage of air through unnecessary oints and valves.

The final clarification of the separated liquid, and the separation therefrom of very minute particles of solid matter such asv cannot be direc Vly separated by centrifugal force, may be facilitated by placingtilterbeingof any suitable material, and supported invany suitable manner. ln Fig. 3 said screens are shown as a perforated ring covered with suitable filtering material arranged a short distance inside of the outer wall of the trough (38, and said trough is preferably fixed to said pipe l, and revolved therewith. One or more outlets 76 from said trough (3S discharges the filtered liquid into another annular stationary trough TS from which it is removed by any suitable fixed on the conveyer shaft above the upper end of the casing 14, and in such a position as to cut or scrape off the upper end of the plug, as the same is workedup by the conveyer, and deliver it into the said trough Said scraper may be of any desired construction as a wheel with scraping or cutting blades, and it will be understood that scrapers .and filtering screens may be used with all forms of the machine.

'l`o prevent. spilling the discharged plug and liquid over their respective troughs 25, 3J( and (3S, the tops of said troughs should preferably be partly covered, about as indicated in the drawings, and the discharge end of pipes 33 will preferably be directed so as to discharge the iiquid in a tangential direction opposed to the direction of revolution of the machine and not radially.

In place of the worm conveyers andl cas ings shown in .the drawings and hereinbefore described, any `other 'suitable forni of conveyer and `asing may be employed, it only being necessary that the conveyers and casings be so constructed and arranged as to convey the concentrates externally to the separation chambers and in such direction 1ft-'haetthe mot-ion of the concentrates pro-l duced by lthe conveyers is opposed to the motion which would be induced by the centrifugal force.

Now having described our improvements we claim as our invention.

l. The combination in centrifugal separators of a sepa ating chamber of relatively greatradial dimension, and a nozzle for the t'lischarge of the heavy concentrated materials extended externally from said chamber to a point nearer the axis of rotation than the extremity of said chambers.

2. The combination in centrifugal separators, of a sepanatiiig chamber of relatively great radial dimension,- a nozzle for the discharge of the heavy'I concentrated materials extended. externally from said chamber to a point nearer the axis of rotation than is the extremity of said chamber, and a coiiveyer for removing` said concentrated materials from said nozzle.

3. The combination in a centrifugal separator, of a separating chamber of relatively great radial dimension and having a concentrating space of relatively small cross section, a nozzle extended externally from said chamber to a point` of discharge nearer the laxis of rotation than is' the extremity of said chamber, and a conveyer for moving the said concentrates through said nozzle.

The combination in centrifugal separators. of a separating vessel of relatively great radial dimension and having a concentrating space of relatively small cross section, a nozzletfor the discharge of the heavy concentrated materials extended cxternally from said chamber to a point nearer the axis of rotation than is the extremity ot' said chamber, and a discharge conduit for the liquid separate from said nozzle.

The combination in a centrifugal separator, of a separating chamber of relatively greatrzulial dimension and having a concentrating space ofrelatively small cross seetion, a nozzle extended externally therefrom' to a point of discharge nearer the axis of rotation than is the extremity of said chamber. a ccnveyer for inmfing the said coiicentrates through said nozzle, and a discharge conduit for the liquid separate from said nozzle.

t3. The combination in a centrifugal inachine of a reservoir for the mixture to be separated, a revolving separating chamber connectedtherewith and having relatively great radial'dimension and a concentrating space of relatively small cross area, a nozzle for the discharge of the heavy concentrated materials external to said chamber and tending nearer the axis of rotation than is I he extremity of said chamber, and an outlet for liquid separate from said nozzle.

7. The combination in a centrifugal machine of a reservoir for the mixture to be separated, a revolving separating chamber '40 pressure lower thanl atmospheric pressure 1n with an outlet connected ltherewith and having relatively great radial dimension, a nozzle for the discharge of the heavy concentrated materials yexternal to saidl chamber and extending 9. In a centrifugal machine, a rotary separating chamber provided with an outlet for the discharge of the heavier concentrated materials, and means adapted to produce unbalanced atmospheric pressure to prevent the eiiiux of the lighter liquid from `said outlet.

10. In a centrifugal machine, a rotary separating chamber provided With an outlet.

for the discharge of the heavier concentrated materials, and. with an independent outlet for the discharge of the lighter liquid, and means adapted to produce unbalanced atmospheric pressure to prevent the eillux of liquid with said heavier' concentrated materials. i'

1l. In a centrifugal machine, the combination of a separating chamber, and a valve in operative communication therewith and adapted to maintain ressure lower than atmosphere in a part ofsaid chamber.

` 12. In a .centrifugal machine, the combination of a se aratin chamber provided with an outlet or heavier concentrated materials, and -a valve adapted to maintain a part of said separating chamber nearer. to

`the axisiof rotation than is said outlet.

' 13. In a centrifugal machine, the combi-4 nation of a se arating vchamber provided or the heavier concentrated materials, and with an inlet for mixed materials, and a valve controlling said inlet and adapted to maintain lower than atmospheric pressure in a part of said chamber nearer to the axis of rotation than is said outlet.

14. In .a centrifugal machine, a rotary separating chamber having relatively great radial dimension "and a concentrating space of relatively small cross area and containing less'than atmospheric pressure in a part of said chamber nearer the axis of rotation than is said concentrating space.

15. In a centrifugal machine, a rotary separating chamber having relatively great radial dimension and a concentrating space of relatively small cross area and contain, ing less than atmospheric pressure in a part of said chamber, said chamber being pro vided with an outlet for heavy concentrated material, and with a separate conduit` for lighter liquid extended from said cham ber to a point where the centrifugal force is substantially equal to atuiospheric pressure.

16. The combination in a centrifugal machine, of a separating chamber containing less than atmospheric pressure in a part thereof and provided with an outlet for the heavy concentrated material and With a conduit for liquid'extendcd from said. chamber to a point where thel centrifugal pressure substantially equals atmospheric pressure.

17. The combination in a centrifugal machine, of a separating chamber containing less than atmospheric pressure ina part thereof, and a conveyer adapted to convey the heavy materials to va point nearer the axis of rotation than is the line of atmos pheric pressure.

18. The con'ibination in a centrifugal machine, of a separating chamber containing less than atmospheric pressure in a part thereof, a conduit for liquid extended from said chamber to a point of substantially atmospheric pressure, an external knozzle separate from said liquid conduit, and ai,

conveyer adapted to move the heavy ma-` terials 1n said nozzle to a point nearer the axis of rotation than is the line of atinos-,

pheric pressure.

19. .The combination in a centrifugallmachine 4of a separating chamber containing less than atmospheric pressure in a part thereof and provided remote from the axis of revolution with a trapped outlet, and a valve controlling the area of the orifice through which materials to be separated are supplied to said separating chamber.

20. The combination in acentrifugal ma.

chine, of av separating chamber containing less than atmospheric pressure in apart thereof and provided remote from the axis of revolution with a trapped outlet for separated materials and with an inlet, and a valve controlling the orifice through which the' mixture is supplied to said separating chamber.

21. The combination in a A','centrifugal machine, of a separating chamber adapted to contain less than atmospheric pressure in a part thereof, a reservoir for the materials to-be separated, and a valve operated by the lieiglit of liquid in the reservoir for con trolling the orifice through which the mixture is supplied to said chamber. 4

Q2; The combination in a centrifugal machine. of a separating chamber containing less than atmospheric pressure in a part thereof, a reservoir for materials to be separated, and Aa linut-controlled valve for i-. riil'i-i lliiig the orifice through 'which said imiterials are supplied to said chamber.-

Q. The combination in a centrifugal ina chine, of a reservoir, a revolving separating pressure 1n said separating chan'ilier.

chamber connected therewith and provided l with an outlet for the discharge of thet heavy concentrated inaterials and with an independent outlet tor the discharge of the lighter liquid substantially at the line ot i atmospheric pressure, a valve controllingl the inlet 'to said separating chamber and adapted to maintain' less than atmospheric pressure in said separating chamber, and a tloatadapted to open and close sa'id valve according to the level ot the mixture in said reservoir. t

' 24. The combination in a centrifugal machine, ot a separating chamber provided with an outlet tor the disch-argent' the heavy separated materials, and with a conduit tor the discharge of the lighter' liquid substantially at the line otf atmospheric'pressure trapped to preventI the entry ol air, and a valve to i'naintain less than atmospheric The combination in a centrifugal machine, ofa reservoir tor the materials to be separated, a revolving separating vessel connected with said reservoir, and provided with an outlet tor the discharge otI the heavy concentrated materials and with an independent trapped outlet. tor the discliarge ot the lighter liquid at substantially the line ct' atmospheric pressure, a valve controlling the inlet to said separating chamber and adapted to maintainl less than atmospheric pressure therein, and means operated by the level of the materials in said reservoir tor opening and closing said valve.

26. ln a centrifugal machine, a separating chamber provided with an outlet t'or the discharge of heavy solid materials, a separate outlet t'or the discharge o'tliquid distant therefrom and extended substantially to the line ot atmospheric pressure, and with a partition extended into said chamber to a point. intermediate ot said outlets.

27. The combination in a centrifugal separator, ot' a separating chamber` a nozzle for the discl arge ot heavy materials, a l t-.onif'eyer for conveying said materials along said nozzle, and a scraper adapted to reiinove portions yof said materials. t

2S. The combination in a centrifugal inal chine. ot' a separating chamber` providedi with an outlet tor the discharge et heavy l materials and with a conduit tor the discharge ot liquid opened to atniosphere substantially at the line ot atmospheric pressure,a discharge pipe trom said conduit, and a discharge receptacle adapted to re- 2t).'l`he combination in a centrifugal machine, ot'. a separating chamber'. -a reservoir i operatively connected therewith, a tlcat chamber, a float therein. and a valve operatively connected with said tloat and adaptedl tocontroltheinlet orifice to said chamber l according the level ot the cmixture inthe float. chamber and maintain less than atmos plieric pressure in said chamber'.

30. In a centrifugal machine, the comv4 bination with a rotary reservoir o't a plurality ot separating chambers each being of relatively great radial dimension and having a relatively contracted concentrating space, and each said chamber containing less than atmospheric pressure in a part thereol nearer the axis ot rotation than is said concentrating space and having an outlet for the discharge ot liquid extended substantially to the line ot atmospheric pressure.

ill. ln a centrit'ugal se]'iarator, the coms binatioii with a rotary reservoir ot a. plurality ot separating chambers each provided with an external nozzle lfor the discharge ot heavy materials extended to a point nearer the axis ot rotation than is the extren'iitv ot said chamber.

In a centrifugal machine, the cour bii'iation with a rotary reservoir, of a plurality ot' separating chambers operatively coi'inected there 'ith, and each said chamber containing less than atmospheric pressure in a part thereof. v

In a centrifugal. separator', the combinat-ion with a rotary reservoir, oit a plurality ot separating chambers each provided with a nozzle for the discharge ot' heavy materials extended externally to said chamber to a point nearer the axis of rotation than the extremity ot' its said chamber, and with an outlet for liquid extended substantially to the line ot atmospheric pressure. y

34. The' combination in a centrifugal machine, ot a rotar)7 reservoir, a plurality ot separating chambers connected therewith, each being ot' relatively great radial dimension and having a relatively contracted concentrating space and haring less than atmospheric pressure in a part ot' each said chamber. and each said chamber having an outlet for the discharge of heavv materials extended to a point, nearer the axis ot" rotation than is the point ot atmospheric pressure` and an outlet tor the discharge ot liquids extended substantially to the line otI i atmospheric pressure.

35. ln a centrifugal machine. a separating chamber provided with an outlet tor the discharge ol the heavy materials from a part ot' the chamber where the ':entritugal torce is relatively great and with an outlet tor the discharge ot liquid opened to l Y atmosphere at a point where the centrifugal ceive the discharge troni said pipe. t

torce ot' said liquid substantially equals atmospheric pressure, and a valve controlling the inlet oritice for the supply to Said chamber ot' materials to be separated.

ln a centrifugal machine, "the'combination of a reservoir, a plurality of. separating chambers connected therewith, and each saidchamber being provided with an maaier@ outlet for the dischargeof heavy materials lfrom a part of the chamber Where the cen trifugal force is relatively great and with anoutlet for the'discharge of liquid, opened 5` to atmosphere at a point Where the centrifugal force of the liquid substantially equals atmospheric pressure. v 37. ln a centrifugal machine, the com loination of a reservoir, a plurality of sepa- 10 rating chambers' connected therewith and With an outlet for the discharge of liquid opened to atmosphere at a point Where the centrifugal force of the liquid substantially equals atmospheric pressure, and a valve controlling the supply inlet for the materials to be separated in said chamber.

Signed at New York city this 15th day of March, 1909.

HARALD DE RAASLGFF. THOMAS E. BROWN.

Witnesses:

HERMAN J. RUBENSTEIN, JNO. L. BERNSTEYIN'. 

